What's your OTL tube amp experience and suggestion?


Are OTL amps in general much less reliable due to their nature, or due to the implementation quality, or both?

Perhaps this has been discussed a zillion times in the past.   Perhaps, however, makers have now improve on past experience?  So it could be worth re-visiting.

My past encounters with OTL tube amps are among the most negative: Wonderful (but never great) sound during the brief period that they work.  Otherwise, major fire hazard.  Overheating, red hot plates, sparks, consistently toasted fuses, burning smell, you name it.  My past OTL amps are like crying babies on an changing table - don't you ever walk away from an arm's distance.   The used market seem to reflect such as well --- way more 'as-is for parts' or 'totally refurbished' units than reliable 'used' units that rarely need service.

Beg your pardon if it's just my poor judgement that keep getting the lemons.   What's your experience, and tips to keep OTL amps up and running happily?


bsimpson
Dear Ralph,

Thank you for your reply!

Alieno swears up and down that semi-conductors are not doing any heavy lifting, and that the amp is not a hybrid amp, and that only tubes are providing both the voltage and the current amplification. Somehow the big power supply allows the KT-150 allegedly to generate the current for the 300B.

What is your theory about how this might be possible?

Ron


300B can not produce that much power. Something fishy about those amps.
If you want Reliability, Service, Sound Quality, Years of Enjoyment i wholeheartedly recommend Atma-Sphere Gear, Nothing like it.  I have bought and sold amplifiers in my 20 years in this hobby and finally settled with the Atma-Sphere.  This is coming from someone who used Single Ended Designs, Push Pull, Solid States, Hybrids. 

The only issue you will find with these amps is paring with the right speaker it can be challenging at times if your speaker has an unusual load. If you get pass this stage you will experience something in audio which most audiophiles strive for but never reach. Pure Musical Bliss!!!

You should visit John Wolff Of Classic Audio Loudspeakers and see what he has done with this Atma-Sphere paired with the high sensitive speakers.
Alieno swears up and down that semi-conductors are not doing any heavy lifting, and that the amp is not a hybrid amp, and that only tubes are providing both the voltage and the current amplification. Somehow the big power supply allows the KT-150 allegedly to generate the current for the 300B.

What is your theory about how this might be possible?
If what you say is true, no need for the semiconductors then, right? But apparently they are needed for something. Think about it.

A single 300b is good for about 7 watts. That's it. When you look at those amps, you don't see a lot of 300bs, so the math is not hard to work out- the 300b isn't making the power. Something else it, and its not the KT150...
Dear Ralph,

Where are you seeing semi-conductors?  In the tube section of the Alieno, or in its power supply?

Are you assuming a solid-state amplification stage based on the heat sink fins of the power supply unit?